Cosmos DB Output binding shall support Bulk Execution mode for high throughput scenarios

[petr-hollay]

The binding must support Bulk Execution mode by setting the following property:
https://docs.microsoft.com/cs-cz/dotnet/api/microsoft.azure.cosmos.cosmosclientoptions.allowbulkexecution?view=azure-dotnet

Expected behavior

Bulk Execution can be set in the binding attributes for compiled C# Functions.

Actual behavior

Build Execution mode can not be set using the existing output binding.

Known workarounds

Go around the standard output binding and use Cosmos DB SDK directly.

Related information

Introducing Bulk support in the .NET SDK - Azure Cosmos DB Blog (microsoft.com)

Bulk support improvements for Azure Cosmos DB .NET SDK - Azure Cosmos DB Blog (microsoft.com)

[ealsur]

Thanks for the suggestion and feedback.

The problem with having this as a configuration attribute is, if the user sets it and then in the function calls sequentially the save method, then they are shooting themselves on the foot.

[FunctionName("WriteDocsIAsyncCollector")]
public static async Task Run(
    [QueueTrigger("todoqueueforwritemulti")] ToDoItem[] toDoItemsIn,
    [CosmosDB(
                databaseName: "ToDoItems",
        containerName: "Items",
                WithBulkMode = true,
        Connection = "CosmosDBConnection")]
        IAsyncCollector<ToDoItem> toDoItemsOut,
    ILogger log)
{
    foreach (ToDoItem toDoItem in toDoItemsIn)
    {
        await toDoItemsOut.AddAsync(toDoItem);
    }
}

That will generate more latency.

There is no API on IAsyncCollector that can avoid this pitfall at the moment.

[ealsur]

Another biggest issue is that Bulk mode in C# depends on customers concurrently executing operations. Because other languages (Python/NodeJS/etc) use Bundles that run on top of C#, how does this work on other languages as well? Do all languages support concurrent execution? Isn't NodeJS single thread?

[praneeth-nimmagadda]

Is Bulk Execution mode supported in the cosmos output triggers?. I don't see that option at all , is there any specific version to see the bulk execution mode option ?

[ealsur]

No, it is not supported as explained in the existing comments.